Fluid hydroforming



Aug. 28, 1956 R. J. FRITZ ET AL' 2,760,910

FLUID HYDROFORMING Filed Dec. 26, 1951 2 Sheets-Sheet 1 ERODUCT OUTLETQEA QQ 1 1 42k "1' 3' IL-1a a; I

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I REGENERATION 6A5 Fr.i

Qo'ben: JI- ritz John F. moser', J'r.

55 W Clttoro e5 United States Patent FLUID HYDROFORMING Robert J. Fritz,John F. Moser, Jr., Lloyd A. Nicolai, and Edward W. S. Nicholson, BatonRouge, La., assignors to Esso Research and Engineering Company, acorporation of Delaware Application December 26, 1951, Serial No.263,444

3 Claims. (Cl. 196-50) This invention relates to the catalyticconversion of hydrocarbon fractions boiling within the motor fuelboiling range of low knock rating into high octane number motor fuelsrich in aromatics and particularly to a process whereby such aconversion is effected by the fluidized solids technique.

I-Iydroforming is a well known and widely used process for treatinghydrocarbon fractions boiling within the motor fuel or naphtha range toupgrade the same or in crease the aromaticity and improve the antiknockcharacteristics of said hydrocarbon fractions. By hydroforming isordinarily meant an operation conducted at elevated temperatures andpressures in the presence of solid catalyst particles and hydrogenwhereby the hydro carbon fraction is increased in aromaticity and inwhich operation there is no net consumption of hydrogen. Hydroformingoperations are ordinarily carried out in the presence of hydrogen orhydrogen-rich recycle gas at temperatures of 750-1150" F. in thepressure range of about 50-1000 lbs. per sq. inch and in contact withsuch catalysts as molybdenum oxide, chromium oxide or, in general,oxides or sulfides of metals of Groups IV, V, VI, VII and VIII of thePeriodic System of elements, alone, or generally supported on a base orspacing agent such as alumina gel, precipitated alumina or zinealuminate spinel. A good hydroforming catalyst is one containing aboutwt. per cent molybdenum oxide upon an aluminum oxide base prepared byheat treating a hydrated aluminum oxide or upon zinc aluminate spinel.

It has been proposed in application Serial No. 188,236, filed October 3,1950, to effect the hydroforming of naphtha fractions in a fluidizedsolids reactor system in which naphtha vapors are passed continuouslythrough a dense, fluidized bed of hydroforming catalyst particles in areaction zone, spent catalyst particles are withdrawn from the dense bedin the reaction zone and passed to a separate regeneration zone whereinactivating carbonaceous deposits are removed by combustion whereuponthe regenerated catalyst particles are returned to the main reactorvessel or hydroforming reaction zone. Fluid hydroforming as thusconducted has several fundamental advantages over fixed bed hydroformingsuch as (1) the operations are continuous, (2) the vessels and equipmentcan be designed for single rather than dual functions, (3) the reactortemperature is substantially constant and (4) the regeneration orreconditioning of the catalyst may be readily controlled.

A particular advantage of the foregoing fluid solids operation has beenthe fact that the freshly regenerated catalyst can be utilized to carrypart of the heat required for the hydroforming reaction from theregeneration zone into the reaction zone. It has been proposed in thisconnection to discharge hot, regenerated catalyst particles from theregenerator standpipe into a stream of hot, hydrogen-rich recycle gas ina transfer line whereby the catalyst particles are subjected to areconditioning treat ment involving at least a partial reduction ofhigher oxides of the catalytic metal formed during regeneration to areaction zone.

lower or more catalytically active form of catalytic metal oxide duringits passage through the transfer line into the In view of the hightemperature of the regenerated catalyst (1100l300 F.) and the exothermiccharacter of the reaction between the hot, freshly regenerated catalystand the hydrogen it is necessary to make the transfer line very short inorder to keep the time of contact of the catalyst andhydrogen-containing gas sufficiently short to avoid overtreatment and/orthermal degradation of the catalyst.

It is the object of this invention to provide a novel method fortreating freshly regenerated hydroforming catalyst preparatory torecycling the same to a fluidized solids hydroforming reaction zone.

it is a further object of this invention to provide a novel method fortreating the freshly regenerated hydroforming catalyst at hightemperatures for very short periods of time.

It is also an object of this invention to provide a novel method fortreating freshly regenerated hydroforming catalyst at high temperaturesfor short periods of time while causing the gaseous products from thepretreatment to by-pass the main reactor bed.

These and other objects will appear more clearly from the detailedspecification and claims which follow.

It has now been found that hot, freshly regenerated hydroformingcatalyst can be pretreated with a hydrogencontaining gas at hightemperatures and for extremely short periods of time if contact of thehot regenerated catalyst, preferably after stripping the samesubstantially free of combustion gases, is made with a high velocitystream of hot, hydrogen-rich gas which conveys the regenerated catalystto the upper part of the reaction zone where the catalyst particles arerapidly separated from the pretreatment gases and deposited in the mainfluidized bed of catalyst. In this way contact of freshly regeneratedcatalyst with hydrogen-rich gas can be kept as short as desired, thehydrogen content of the pretreating gas can be varied by dilution withinert gases to any desired extent Without affecting the superficialvelocity of gases and vapors through the dense fluidized catalyst bed inthe reaction zone, and any water vapor formed in the pretreatment isby-passed around the dense fluidized bed thereby avoiding the poisoningeflect of water vapor upon the catalyst under hydroforming reactionconditions.

Reference is made to the accompanying drawing illustrating twoembodiments of the present invention.

Fig. 1 is a schematic flow plan of a reactor-regenerator systemembodying a high temperature, short time catalyst pretreatment, and

Fig. 2 is a modification of the reactor-regenerator system in which thepretreatment riser is arranged within the reactor vessel.

In Fig. l, 10 is a reactor vessel provided at the bottom with an inletline 11 for the introduction of hot hydrogenrich or recycle gas. Aperforated plate or distributor grid 12 is arranged within the vesselfor insuring uniform distribution of the incoming recycle gas over theentire cross-section of the reactor vessel. A separate inlet line 13connected to a distributor ring 13 is shown for the introduction ofnaphtha feed above the grid member 12, although the feed may, ifdesired, be introduced separately or along with the recycle gas belowthe grid. The reactor vessel 10 is charged with finely dividedhydroforming catalyst particles and the superficial velocity of thevapors and gases through the vessel is so controlled as to form a dense,fluidized, turbulent bed of catalyst 14 having a definite level or uppersurface L superposed by a dilute or disperse phase 15 comprising smallamounts of catalyst entrained in vaporous reaction products. Thereaction products are taken overhead from the reactor, preferablythrough a cyclone separator 16 or the like for separating entrainedcatalyst particles which are returned to the dense bed 14 via the dipleg attached to the bottom of the cyclone separator. Reaction productsare conducted via outlet line 17 to suitable separating, fractionating,pressure release and/or storage equipment.

Catalyst particles are continuously Withdrawn from the dense bed 14-through withdrawal conduit 155 into an external stripper vessel 19. Itwill be understood that the stripper could also be arranged within thereactor vessel as by providing a vertical conduit or cell, preferably extending above dense bed level L and provided with an orifice or port forcontrolling the discharge of catalyst into the stripper cell or conduit.A tap 20 is arranged in the lower portion of the stripper forintroducing a suitable stripping gas such as steam, nitrogen, flue gaspreferably washed free of carbon oxides, or other gases wl ich wiilserve to remove entrained or adsorbed hydrogen or hydrocarbon materialsthat would otherwise be carried to the regeneration zone and burnedtherein. The stripping gas and stripped gases are withdrawn overheadfrom stripper 19 and passed through line 21 into the upper part ofreactor vessel it? in the event that substantial amounts of catalyst areentrained and recovery thereof in reactor cyclone separator 16 isdesired, or through line 22 to product outlet line 17 in the event thatit is desired to have the stripping gas by-pass the reactor. The lowerend oi. the stripping vessel 19 is necked down and forms with conduit 23connected to its lower end a standpipe for developing sufiicientfluistatic pressure for oifsetting the pressure drop through theregenerator side of the system. A slide valve 2d or the like is providedto control the withdrawal of catalyst from the reactor vessel and ifdesired or if necessary to maintain the catalyst in a fluidized stateone or more gas taps can be provided along standpipe 23 to supplyfluidizing gas.

The slripoed spent catalyst is discharged from the base of standpipe 23into transfer line 25 Where it is picked up by a stream of regenerationgas or air and conveyed into the bottom of regenerator vessel 3%. Aperforated plate or grid member 51 is preferably arranged at the bottomof the regenerator vessel to insure uniform distribution of the catalystand gases over the entire cross section of the regenerator. In order toavoid oveitreatment of the spent catalyst in transfer line 25 it ispreferable to use only part of the air necessary for regeneration forconveying the spent catalyst through transfer line 25 and to add theremainder of the air necessary for regeneration through a separate line32 or additional lines discharging directly into the regenerator vessel.In view of the fact that the oxidative reactions that occur in theregenerator generate more heat than can normally be transferrcd to thereactor by the circulating catalyst at low catalyst to oil ratioswithout exceeding safe temperature limits. it is ordinarily necessary toprovide cooling coils in the regenerator to prevent the regeneratortemperature from exceeding a safe upper limit of about 12001300 A verydesirable arrangement is to provide a primary cooling coil entirelybelow the level L and a secondary coil partly below and partly above thedense bed level L to permit adjustment of the heat exchange capacity bysimply varying the dense bed level L in the regenerator.

The superficial velocity of the regeneration gases through vessel 30 isso controlled as to form a dense, fluidized turbulent bed 33 of catalystparticles and gas having a definite level L superposed by a dilute ordisperse phase 34 in the upper part of the regenerator comprising smallamounts of catalyst entrained in the regeneration gases. Theregeneration gases are taken overhead from regenerator 30 preferablyafter passage through a cyclone separator 35 or the like which serves toremove most of the catalyst particles from the gases. The catalystparticles are returned to the dense bed 33 through the dip pipe attachedto the bottom of the cyclone separator. The regeneration gases,substantially free from catalyst particles, are withdrawn overhead vialine 36 and passed through a pressure control valve 44 to a waste gasstack or to suitable storage equipment in the event that it is desiredto use the regeneration gases for stripping purposes.

Regenerated catalyst is withdrawn from the dense bed 33 through conduit37. Stripping gas such as air, flue gas or the like is introduced intoconduit 37 through taps 38 and 39. A preferred operation is to firststrip the regenerated catalyst with air, introduced at 38, to effect afinal clean up of the catalyst and then with nitrogen inl danced at topurge the regenerated catalyst stream of air and any residual amounts ofcarbon monoxide or carbon dioxide.

The stripped regenerated catalyst is discharged from conduit 37 throughslide valve or the like into transor line Sufficient hydrogen-rich orrecycle gas is supplied through line 41 to convey the regeneratedcatalyst through riser 42 into the top of the reactor 19. it preferredto keep the transfer line and riser as small in diameter and as short aspossible in order to keep the time of contact of the hot regeneratedcatalyst with the hydrogen-rich gas to a minimum. Specifically the resideuce time of the hot regenerated catalyst in contact with thehydrogen-rich gas should be less than about 10 seconds and preferablyonly about one to two seconds. The mixture of hot regenerated catalystis discharged into a cyclone separator 43 or the like in order todisengage the hot catalyst from the hydrogen-containing gas as rapidlyas possible. While this separator is shown inside the reactor it isobvious that it could be arranged externally of the reactor in whichcase a suitable connector pipe would be provided for conducting theseparated catalyst particles into the reactor dense bed 14. The gasesmay discharged from separator 4-3 into the dilute phase 15 or directlyinto cyclone separator 16 to effect further separation of catalystparticles or the gases may be passed from cyclone separator 43 toseparate recovery or processing equipment.

Fig. 2 illustrates a modification of the reactor-regenera or system inaccordance with the present invention. In this embodiment is the reactorvessel, 111 the recycle gas inlet line, 112 the distributor giid, 113the separate feed inlet and 113 a distributor ring for introducing freshfeed above the grid 112. 114 is the dense fluidized bed having adefinite level L or dense bed-dilute phase interface and 115 is thedilute or disperse phase in the upper part of the reactor vessel while116 is the cyclone separator for separating entrained catalyst from thereaction products that are withdrawn from the reactor lltl through line117 and passed to suitable product recover pressure release and/0rprocessing equipment. Catalyst is withdrawn from the dense bed 114through outlet line 118 into stripper 115 where it is contacted withsuitable stripping gas introduced through inlet line 120. Stripping gasand stripped products are taken overhead from stripper 119 anddischarged either through line 121 into the dilute phase 115 in theupper part of reactor 110 or through line 122 into reaction productsoutlet line 117 when it is desired to have the stripping gas by-pass thereactor completely.

The lower end of stripper 119 is necked down and is attached to conduit123 forming therewith a standpipe for facilitating transfer of catalystto the regenerator. A slide valve 124 is provided at the base of thestandpipe for controlling the withdrawal of catalyst from the reactor110. Spent catalyst is discharged from standpipe 123 into transfer line125 where it is picked up by a stream of air and carried intoregenerator vessel 130. 131 is the distributor grid and 132 is a linethrough which the major proportion of the regeneration air is suppliedto the regenerator. 133 is the dense fluidized bed of catalyst in theregenerator, L is the level of the dense bed and 134 is the dilute ordisperse phase in the upper part of the regenerator vessel. 135' is thecyclone separator for removing entrained catalyst from the regenerationgases while 136 is the outlet line for regeneration gases which isprovided with a pressure release valve 147 and discharges regenerationgases to a flue 'or to storage equipment if the regeneration gases areto be used for stripping purposes. Cooling coils (not shown) preferablyas described above in connection with Fig. .1 are provided inregenerator 130 to control the temperature of the regenerated catalyst.

Regenerated catalyst is withdrawn from dense bed 133 through line 137into stripper 138. Stripping gas, for example air, is introduced intothe stripper through tap 139, the stripping gas preferably passingoverhead from the stripper into the upper part of vessel 130. Thestripper 138 is connected to conduit 140 and forms therewith a standpipefor facilitating the transfer of regenerated catalyst to the reactorside of the system. Additional stripping gas such as nitrogen or fluegas which has been freed of carbon dioxide and carbon monoxide isintroduced at 141. A slide valve 142 is provided at the base of thestandpipe for controlling the discharge of stripped regenerated catalystinto transfer line 143. A stream of hydrogen-rich gas is introduced intotransfer line 143 through line 144 in order to convey the regeneratedcatalyst through the transfer line 143 and regenerated catalyst riser145 into the upper part of the reactor vessel. As in the case of thetransfer line and riser of Fig. 1 it is advisable to keep these elementsas short as possible and of as small diameter as possible in order tokeep the time of contact of the hot regenerated catalyst with therecycle or hydrogen-rich gas stream to a minimum. The arrangement shownin Fig. 2 is particularly advantageous since the dense reactor bed 114in contact with a substantial length of the regenerated catalyst riser145 serves to exert a cooling action upon the mixture of regeneratedcatalyst and hydrogen-rich gas. The mixture of regenerated catalyst andhydrogen rich gas is discharged from the riser 145 substantially at thedense bed level L, preferably against a baflle 146 or the like, arrangedjust above the dense bed level, in order to cause a substantialseparation of catalyst from the gas stream for direct addition to thetop of the dense bed 114.

The feed or charging stock to the hydroforming reactor may be a virginnaphtha, a cracked naphtha, a Fischer- Tropsch naphtha or the like. Thefeed stock is preheated alone or in admixture with recycle gas toreaction temperature or to the maximum temperature possible whileavoiding thermal degradation of the feed stock. Ordinarily preheating ofthe feed stock is carried out to temperatures of about 800-1050 F.,preferably about 1000 F. The naphtha preheat should be as high aspossible while avoiding thermal degradation thereof as by limiting thetime of residence in the transfer or feed inlet lines. The preheatedfeed stock may be supplied to the reaction vessel in admixture withhydrogen-rich recycle gas or it may be introduced separately as shown.The recycle gas, which contains from about 50 to 70 vol. percenthydrogen, is preheated to temperatures of about 1150-1300 F., preferablyabout 1200 F. prior to the introduction thereof into inlet line 11. Themajor proportion (at least 85%) of the recycle gas is introduceddirectly into the bottom of the reactor vessel while a minor proportiononly (at most about 15%) is introduced into the regenerated catalysttransfer and pretreater line. The recycle gas should be circulatedthrough the reactor at a rate of from about 1000 to 8000, preferablyabout 4000, cu. ft. per barrel of naphtha feed.

The reactor system is charged with a mass of finely divided hydroformingcatalyst particles. Suitable catalysts include Group VI metal oxides,such as molybdenum oxide, chromium oxide or tungsten oxide or mixturesthereof upon a carrier such as activated alumina, zinc alurninate spinelor the like. Preferred catalysts contain about 5 to wt. molybdenum oxideor from about 10 to 40 wt. chromium oxide upon a suitable carrier. Ifdesired, minor amounts of stabilizers and promoters such as silica,calcium oxide, ceria or potassia can be 6 included in the catalyst. Thecatalyst particles are, for the most part, between 200 and 400 mesh insize or about 0-200 microns in, diameter with a major proportion between20 and microns.

The hydroforming reactor vessel should be operated at temperaturesbetween about 850 and 950 F., preferably about 900 F. and at pressuresbetween 50 and 500 lbs. per sq. inch. Temperatures above 900 F. resultin increased carbon formation and lower selectivity to gasolinefractions while at temperatures below about 900 F. operating severity islow and would therefore require an excessively large reaction vessel.Lowering reactor pressure below 200 lbs. per sq. inch ordinarily resultsin increased carbon formation which becomes excessive in most cases atpressures below about 75 lbs. per sq. inch. Above 200 lbs., however,catalyst selectivity to light products (C4s and lighter) increasesrapidly.

The regenerator is operated at essentially the same pressure as thereactor and at temperatures of about 1050-1300 F. The residencetime ofthe catalyst in the reactor may be of the order of 3-4 hours while theresidence time of the catalyst in the regenerator may be from about 3 to15 minutes. The superficial velocity of the gaseous or vaporousmaterials through thereaction and regeneration zones is about 0.2 toabout 0.9 foot per second. I

The weight ratio of catalyst to oil introduced into the reactor shouldbe about 0.5 to 1.5. It is preferred to operate at catalyst to oilratios of about 1 since ratios above about 1 to 1.5 result in excessivecarbon formation. Somewhat higher weight ratios can be used at higherpressures. I

Space velocity, or the weight of feed in pounds charged per hour per.pound of catalyst in the reactor, depends upon the age or activity levelof the catalyst, the character of the'feed stock and the desired octanenumber of the product. Space velocity for a molybdenum oxide on aluminagel catalyst may vary, for example, from about 1.5 wt./hr./wt. to about0.15 wt./hr./wt.

In order to demonstrate the effect of small amounts of water vapor uponthe hydroforming reaction, a number of experiments were carried out in abatch-fluid laboratory hydroforming unit during which water vaporequivalent to that formed in pretreatment was added continuously withthe hydrogen-containing gas entering the hydroforming reaction'zone. Thecatalyst was a commercial molybdenum oxide on activated alumina, reactortemperature about 900 F. and the reaction pressure 200 lbs. per sq.inch.

These data are summarized in the following table. Effect of water ofpretreatment on activity and seleczivity of hydroforming catalysts C/ORatio 1 5 1.0 Water of Pretreatment, V01. Percent on Inlet Recycle Gas 00.7 3. 5 7.0 O. N. of Product at Fixed WJHJW. W. 92 91 88 GasolineYield, Vol. Percent 82. 5 82.0 81 79 Carbon Yield 0. 4 0. 5 0. 7 1. 0

1 Operations whereby water of pretreat does not enter reactor.

3 Assume average of 3,000 O. FJB. of recycle gas.

It may readily be seen that the water vapor in every case lowered theyield and octane number of the product and resulted iii-higher carbonyields.

The foregoing description contains a limited number of embodiments ofthe present invention. It will be understood that numerous variationsare possible with out departing from the spirit of this invention.

What is claimed is:

1. In a process for hyd-roforming hydrocanbons in contact with finelydivided hydroforming catalyst particles consisting essentially of aG-roup VI metal oxide on a carrier in accordance with the fluidizedsolids technique at temperatures between about 850 F. and 950 F., atpressures between about 50 and 500 pounds per square nch and at a y t oi1 Wigh a s o abou o bqut -.51 the i p qv m n wh mprise c tinuouslywithdrawing a stream of catalyst particles from the dense fluidized bedin the hydroforming reaction zone, regenerating the withdrawn catalystparticles by burning carbonaceous deposits therefrom at elevatedtemperatures in a separate regeneration zone, withdrawing a stream ofregenerated catalyst particles from the regeneration zone, stripping thewithdrawn regenerated catalyst particles substantially free ofcombustion gases, discharging the stripped regenerated catalystparticles into a high velocity stream of hyrogen-rich gas which rapidlyconveys the regenerated catalyst to the upper part of the reaction zone,rapidly disengaging the catalyst particles from the stream ofhydrogen-rich gas so that the residence time of the hot regeneratedcatalyst in contact with the hydrogen-rich gas stream is less than tenseconds, discharging the said stream of hydrogen-rich gas into theproduct vapors withdrawn from the reaction zone and rapidly depositingthe disengaged regenerated and pretreated catalyst into the main densefluidized bed of catalyst in the reaction zone.

2. In a process for hydro forming hydrocarbon fractions boiling withinthe motor fuel range in contact with finely divided hydroformingcatalyst particles consisting essentially of a Group VI metal oxide upona carrier in accordance with the fluidized solids technique attemperatures of between about 850 F' and 950 1 at pressures betweenabout 50 and 500 pounds per square inch and at catalyst to oil Weightratios of about 0.5-1 to about 1.51, the improvement which comprisescontinuously withdrawing a stream of catalyst particles from a densefluidized bed within the hydroforming reaction zone, stripping adsorbedand entrained hydrogen and hydrocarbons from the catalyst, dischargingthe stripped catalyst particles into a regeneration zone, regeneratingthe catalyst particles by burning carbonaceous deposits therefrom attemperatures of about 1100 F. to 1300 F., withdrawing a stream ofregenerated catalyst particles from the regeneration zone, stripping thewithdrawn regenerated catalyst particles substantially free ofcombustion gases, discharging the stripped regenerated catalystparticles into a high velocity stream of hydrogen-rich gas which rapidlyconveys the regenerated catalyst particles to the upper part of thereaction zone and effects a pre treatment of the regenerated catalyst,rapidly disengaging the catalyst particles from the stream ofhydrogenrich gas so that the residence time of regenerated catalystparticles in contact with the hydrogen-rich gas is less than ten secondsand discharging the mixture of hydrogen-rich gas and regeneratedcatalyst at or above the upper surface of the main dense fluidized bedof catalyst in the reaction zone, whereby the gaseous products of 5pretreatment are intermingled with the vaporous reaction rr ss s in hedisperse Ph e and hu v -pas he an fluidized bed of catalyst in thereaction zone and the regenerated and pretreated catalyst particles arerapidly deposited into the main dense fluidized bed in the reactionzone.

3. In a process for hydroforming hydrocarbon fractions boiling withinthe motor fuel range in contact with finely divided hydroformingcatalyst particles consisting essentially of a Group VI metal oxide upona carrier in accordance with the fluidised solids technique attemperatures of between about 850 F. and 950 F., at pressures betweenabout 50 and 500 pounds per square inch and at catalyst to oil Weightratios of about 0.5-1 to about 1.51, the improvement which comprisescontinuously withdrawing a stream of catalyst particles from a densefluidized bed within the hydroforming reaction zone, stripping adsorbedand entrained hydrogen and hydrocarbons from the catalyst, dischargingthe stripped catalyst particles into a regeneration zone, regeneratingthe catalyst particles by burning carbonaceous deposits therefrom attemperature of from 1100 F. to 1300" F., withdrawing a stream ofregenerated catalyst particles from the regeneration zone, stripping thewithdrawn regenera-ted catalyst particles substantially free ofcombustion gases, discharging the stripped regenerated catalystparticles into a high velocity stream of hydrogenrich gas, passing theresultant minture of regenerated catalyst and hydrogen-rich gas at highvelocity indirect heat exchange to the dense fluidized bed within thereaction zone, whereby the regenerated catalyst particles are rapidlyconveyed to the upper part of the reaction zone while undergoingpretreatment, rapidly disengaging the catalyst particles from the streamof hydrogen-rich gas so that the residence time of regenerated catalystparticles in contact with the hydrogen-rich gas at less then 10 secondsand discharging the said mixture is or above the upper surface of themain dense fluidized bed of catalyst in the reaction zone whereby thegaseous products of pretreatment are directly intermingled with thevaporous reaction products in the disperse phase and thus by-pass themain fluidized bed of catalyst in the reaction zone and the regeneratedand pretreated catalyst particles are rapidly deposited in the maindense fluidized bed of catalyst particles in the reaction zone.

References Cited in the file of this patent UNITED STATES PATENTS2,366,372 Voorhees Jan. 2, 1945 2,410,891 Meinert et al Nov. 12, 19462,459,824 Letter Jan. 25, 1949 2,472,844 Munday et al. June 14, 1949

1. IN A PROCESS FOR HYDROFORMING HYDROCARBONS IN CONTACT WITH FINELYDIVIDED HYDROFORMING CATALYST PARTICLES CONSISTING ESSENTIALLY OF AGROUP VI METAL OXIDE ON A CARRIER IN ACCORDANCE WITH THE FLUIDIZEDSOLIDS TECHNIQUE AT TEMPERATURES BETWEEN ABOUT 850* F. AND 950* F., ATPRESSURES BETWEEN ABOUT 50 AND 500 POUNDS PER SQUARE INCH AND ATCATALYST TO OIL WEIGHT RATIOS OF ABOUT 0.5-1 TO ABOUT 1.5-1, THEIMPROVEMENT WHICH COMPRISES CONTINUOUSLY WITHDRAWING A STREAM OFCATALYST PARTICLES FROM THE DENSE FLUIDIZED BED IN THE HYDROFORMINGREACTION ZONE, REGENERATING THE WITHDRAWN CATALYST PARTICLES BY BURNINGCARBONACEOUS DEPOSITS THEREFROM AT ELEVATED TEMPERATURES IN A SEPARATEREGENERATION ZONE, WITHDRAWING A STREAM OF REGENERATED CATALYSTPARTICLES FROM THE REGENERATION ZONE, STRIPPING THE WITHDRAWNREGENERATED CATALYST PARTICLES SUBSTANTIALLY FREE OF COMBUSTION GASES,DISCHARGING THE STRIPPED REGENERATED CATALYST PARTICLES INTO A HIGHVELOCITY STREAM OF HYROGEN-RICH GAS WHICH RAPIDLY CONVEYS THEREGENERATED CATALYST TO THE UPPER PART OF THE REACTION ZONE, RAPIDLYDISENGAGING THE CATALYST PARTICLES FROM THE STREAM OF HYDROGEN-RICH GASSO THAT THE RESIDENCE TIME OF THE HOT REGENERATED CATALYST IN CONTACTWITH THE HYDROGEN-RICH GAS STREAM IS LESS THAN TEN SECONDS, DISCHARGINGTHE SAID STREAM OF HYDROGEN-RICH GAS INTO THE PRODUCT VAPORS WITHDRAWNFROM THE REACTION ZONE AND RAPIDLY DEPOSITING THE DISENGAGED REGENERATEDAND PRETREATED CATALYST INTO THE MAIN DENSE FLUIDIZED BED OF CATALYST INTHE REACTION ZONE.